Chromecast: mitigate threading issue between AvPipeline/MediaKeys.

chromecast/media/cma/pipeline/av_pipeline_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMECAST_MEDIA_CMA_BASE_AV_PIPELINE_IMPL_H_
 #define CHROMECAST_MEDIA_CMA_BASE_AV_PIPELINE_IMPL_H_
 
 #include <list>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
+#include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "chromecast/media/cma/backend/media_component_device.h"
 #include "chromecast/media/cma/pipeline/av_pipeline_client.h"
 
 namespace media {
 class AudioDecoderConfig;
 class VideoDecoderConfig;
 }
 
 namespace chromecast {
 namespace media {
 class BrowserCdmCast;
 class BufferingFrameProvider;
 class BufferingState;
 class CodedFrameProvider;
 class DecoderBufferBase;
 class MediaComponentDevice;
 
-class AvPipelineImpl {
+class AvPipelineImpl : public base::RefCountedThreadSafe<AvPipelineImpl> {
  public:
   // Pipeline states.
   enum State {
     kUninitialized,
     kPlaying,
     kFlushing,
     kFlushed,
     kStopped,
     kError,
   };
 
   typedef base::Callback<
       void(const ::media::AudioDecoderConfig&,
            const ::media::VideoDecoderConfig&)> UpdateConfigCB;
 
   AvPipelineImpl(
       MediaComponentDevice* media_component_device,
       const UpdateConfigCB& update_config_cb);
-  ~AvPipelineImpl();
 
   // Setting the frame provider or the client must be done in the
   // |kUninitialized| state.
   void SetCodedFrameProvider(scoped_ptr<CodedFrameProvider> frame_provider,
                              size_t max_buffer_size,
                              size_t max_frame_size);
   void SetClient(const AvPipelineClient& client);
 
   // Initialize the pipeline.
   bool Initialize();
 
   // Setup the pipeline and ensure samples are available for the given media
   // time, then start rendering samples.
   bool StartPlayingFrom(base::TimeDelta time,
                         const scoped_refptr<BufferingState>& buffering_state);
 
   // Flush any remaining samples in the pipeline.
   // Invoke |done_cb| when flush is completed.
   void Flush(const base::Closure& done_cb);
 
   // Tear down the pipeline and release the hardware resources.
   void Stop();
 
   State GetState() const { return state_; }
   void TransitionToState(State state);
 
   void SetCdm(BrowserCdmCast* media_keys);
 
  private:
+  friend class base::RefCountedThreadSafe<AvPipelineImpl>;
+  ~AvPipelineImpl();
+
   // Callback invoked when the CDM state has changed in a way that might
   // impact media playback.
   void OnCdmStateChange();
 
   // Callback invoked when playback has reached the end of stream.
   void OnEos();
 
   // Feed the pipeline, getting the frames from |frame_provider_|.
   void FetchBufferIfNeeded();
 
@@ skipping 59 matching lines @@
 
   // Indicate if there is a frame being pushed to the audio device.
   bool pending_push_;
 
   // The media time is retrieved at regular intervals.
   // Indicate whether time update is enabled.
   bool enable_time_update_;
   bool pending_time_update_task_;
 
   // Decryption keys, if available.
+  base::Lock media_keys_lock_;
   BrowserCdmCast* media_keys_;
   int media_keys_callback_id_;
 
-  base::WeakPtr<AvPipelineImpl> weak_this_;
-  base::WeakPtrFactory<AvPipelineImpl> weak_factory_;
-
   DISALLOW_COPY_AND_ASSIGN(AvPipelineImpl);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_CMA_BASE_AV_PIPELINE_IMPL_H_